End Of Summer? Above Average Temperatures This Week But Cooler Weather Ahead 

This week, the US Lower 48 temperature outlook forecasts summer is not over for some parts of the country. 

For the week ending Sept. 11, cooling degree days (CDD) are estimated to be around 60 CDD, 14 CDD above the 30-year long-term trend for this year, which is approximately 44 CDD, according to new data from the NOAA’s National Weather Service (NWS).

For readers who aren’t familiar with CDD, it’s a measure of demand for energy needed to cool a building structure. It’s the number of degrees that a day’s average temperature is above 65F. 

CDD is generally used as a risk management tool for agriculture, construction, utility, and other firms that hedge activities dependent on weather activities. 

In NOAA’s weekly CDD forecast, the most significant outliers on a regional and state basis were: 


  • Mountain: 89 forecasts versus 47 normal
  • Pacific: 74 forecasts versus 34 normal
  • West South Central: 118 forecasts versus 95 normal


  • Utah: 93 forecasts versus 21 normal
  • Nevada: 145 forecasts versus 75 normal
  • California: 86 forecasts versus 44 normal

By the second half of the month, around 17-19, the US Lower 48 temperature outlook is expected to revert to the 30-year mean. Looking at it another way, temperature highs are expected to begin plunging in the second half of the month. 

As temperatures are expected to drop later this month, forecasted heating degree days are also rising, showing that colder weather may force some Americans to turn off their air conditioners for the year and turn up the thermostats. This would imply a rise in energy and electricity prices.  

Already, the search term “propane heater” across the US has reached a new 30 day high.

So expect above-average temperatures this week, but realize that cooler temperatures are on the way, may begin as early as Sept. 17-19.